Air filters presently in use in automotive vehicles, used to filter harmful contaminants such as dust particles from the air intake of internal combustion engines, are made of paper which is pleated to produce a large surface area for entrapment of the particles. Recently a plastic foam filter, consisting of a single sheet of reticulated foam coated with engine oil, has appeared on the market under the trademark FILTRON as a sustitute for a paper filter for internal combustion engines, to reduce costs. However, the FILTRON device does not filter as well as a paper air filter although its life can be extended by washing it.
It is an object of the present invention to provide a foam plastic air filter which exceeds the breathing characteristics, during service life, of a pleated paper air filter.